1. Field of the Invention
This invention generally pertains to the field of manual data input systems. More particularly, the invention relates to combinatorial keyboards and other manual means for data entry in computer terminals, telephone dialing, digital calculators etc..
2. Description of the Related Art
Alphanumeric and control data entry to a computer and other digital machines may be accomplished in several ways using a variety of input devices. A traditional device for manual input is a typewriter keyboard which can be used to input alpha-numeric and control data directly into the computer. Keyboards are also used in a large variety of other digital systems such as: telephones, calculators and typewriter printers. Such keyboards are suggested in many shapes and forms. Widely mentioned in the literature are also touch pads which are just other type of keyboard devices, since they also employ a plurality of pressure locations.
All the keyboard based devices mentioned above suffer from a common drawback: all of them require a large number of keys that occupy a substantial area. In many recent lap-top computers the keyboard is even larger than the display screen. The main reason for the large number of keys in these devices, is that each key is used only for 2-3 input characters. For example, upper case characters and control characters are entered in standard keyboards by depressing two keys at the same time. Since the standard ASCII format used in computer terminals includes 128 different characters, even 3 characters per key still requires more than 40 keys. Another drawback of the standard keyboard is that the keys are arranged in straight rows on a plane, and no effort was made to make this standard arrangement more suitable for the human operator.
Furthermore, typing with a large number of keys requires frequent eye-hand coordination in order to find their location and frequently causes eye fatigue since the user's gaze must be repeatedly diverted from the screen to locate the keys. Some people solve this problem by exercising "blind" typing methods. But such methods require special training due to the large number of keys and are more error prone than non-blind typing methods. Even with eye-hand coordination, fast typing frequently results in many errors since it requires fast finger movements over substantial distances from key to key.
Many efforts have been made to modify the layout of keyboards. A modified keyboard with new assignment of keys was disclosed by Dvorak in U.S. Pat. No. 2,040,248. Malt in U.S. Pat. No. 4,244,659, suggested a curved arrangement for the keys that makes more use of the thumb which is used in standard keyboards only for operation of the space bar. A specific allocation of key for each finger is disclosed by Runge in U.S. Pat. No. 4,265,557. Runge suggested clusters of keys that are allocated for each finger. Each finger operates four keys in a narrowly defined location. Similar approach with five keys per finger was disclosed by Retter in U.S. Pat. No. 4,917,516. Retter placed the keys in finger wells on two ergonomically shaped mouse devices that are also used for cursor control. The keys are operated in left, right, forward, reverse and down directions. Another method was suggested by Winkler in the United Kingdom Pat. No. 2,076,743 where the data entry device employs pressure sensitive switches actuated by the finger knuckles. The systems of Dvorak, Malt, Runge, Winkler and Retter still do not significantly reduce the number of keys required, even though the confined location of operation for each finger alleviates the necessity for eye-hand control in the methods of Runge and Retter. However, these inventions require difficult actuation movements of the fingers especially in the left-right and forward directions. Such operations exert special strain on the muscles especially in left-right directions. The method of Winkler also requires special finger movements. Moreover, many people are not able to move their fingers independently in these directions. Operation of one finger often results in involuntary movement of neighboring fingers as well.
Efforts to reduce the number of keys were made in two major directions. The first direction is to reduce the key number by using key combinations for each character. The second direction employs pivoted keys where each key has multiple positions. The combinatorial approach is disclosed by Eilam in U.S. Pat. No. 4,833,446 where a combinatorial method with 8 keys that are operated by one hand was developed. In U.S. Pat. No. 4,490,056 and U.S. Pat. No. 4,067,431 by Whitaker disclosed a keyboard that has 12 keys. The combinatorial methods overcome the major two-combination limitation of the traditional on/off key by actuating more than one key per character. Various combinatorial and time sequential methods to encode the large number of characters were suggested. However, such methods are quite complicated to memorize and data entry is slow because each character requires a large sequence of manual operations. The major limitation of these methods is the requirement of many on-off keys which have only two positions per key, while our method uses only few multi-position switches with even greater number of combinations. Our approach also replaces the finger operated keys with the natural dexterity of wrists for multi-directional typing.
The second direction mentioned above was disclosed by Hesh in U.S. Pat. No. 2,526,228 where the keyboard was replaced by ten pivoting keys with five directions each. Similar approaches disclosed by Samuel in U.S. Pat. No. 3,633,724 and by Wuenn in Yaeger in U.S. Pat. No. 3,633,724 and by also suggest the same approach of multi-position finger keys that are worn on the fingers. The disadvantages of finger-operated pivoted keys are similar to the disadvantages of the above mentioned methods of the key clusters that are designated for each finger. Pivoted keys operated by fingers also entail difficult and independent movements of the fingers especially in the left-right and forward directions. Such operations exert special strain on the muscles. Moreover, many people are unable to move their fingers independently in lateral directions. Furthermore, such keyboards constrain the fingers to closely confined locations all the time and do not utilize the natural dexterity of the wrist and the arm.
To summarize, finger based methods still require a substantial number of keys, difficult finger movements, or complex sequential typing to encode the large number of characters that are required for alpha-numeric data entry. No effort was made in the above inventions to combine the multi-position keys with combinatorial methods in order to further reduce their total number. The above mentioned inventions also do not utilize the natural dexterity of the wrist and the arm and do not employ their capabilities for multi-directional movements.
Other means for inputting data which use directional manual input, such as: joystick, mouse, data tablets or directional touch pads (see for example, Matzke U.S. Pat. No. 4,736,191), are mainly designed for analog-continuous control input. This kind of input is chiefly required for cursor or pointer control on a terminal screen. In the U.S. Pat. No. 4,823,634 Culver disclosed a tactile device for cursor control based on a rotating cylinder journaled in a movable bar. A similar device was disclosed by Avila in U.S. Pat. No. 4,799,049.
Due to their finely quantized output, and the limited accuracy of human operators, such devices are unsuitable for manual entry of alpha-numeric data without additional visual feedback. In the U.S. Pat. No. 4,916,440, Faeser discloses a device that uses an analog joystick with visual feedback for entering alpha-numeric data. Such methods are extremely slow and ineffective.
Hence, for effective character inputing, the input means should not be of analog nature but should be discrete and should put into use the natural attributes of the human hand especially the wrist and arm capabilities for accurate directional movements. This calls for an entry system with preferably only two hand-operated control knobs with multiple positions that are actuated by discrete directional movements. In addition, such system should be combinatorial in order to achieve a maximum number of input characters with a minimal number of control knob positions. In order to encode the 128 different characters defined in the standard ASCII code with only two hand-operated control knobs, each key should have at least 12 discrete positions which generate 12.times.12=144 input combinations.
Directional, hand-operated input devices, such as multi-position switches or joysticks, that were disclosed, are not suitable for fast directional actuation or have much fewer positions than are required. Typically, such devices have only few input positions (usually four) and are specifically designed for remote control applications such as positioning the vertical and horizontal axes of cursors, rearview mirror adjustments or TV games, and not for manual alpha-numeric data entry. These multi-position switches often include a plurality of contact pairs printed on a PC board that are designated as the switch terminals. Superimposed over each contact pair is a corresponding movable contact usually made of conductive material which is attached to a resiliently deformable diaphragm. When the diaphragm is depressed at the location of the switch terminals the movable contact touches the switch terminals and activates the switch. The diaphragm is depressed by a movable member that is tilted about a central gymball or other central support. Usually the movable member has the shape of a control knob or a joystick.
Typical representations of such devices are disclosed in the U.S. Pat. Nos.: 4,992,631 by Gee, 4,931,781 by Miyakawa, 4,476,356, 4,499,342 and 4,975,547 by Nakayama, 4,896,003 by Hseih, 4,687,200 by Shirai, 4,408,103 by Smith, 5,012,230 by Yesuda, 4,246,452 by Chandler, 4,428,649 by Main.
In order to reduce the total number of parts in such switches, the movable member is restored to a neutral position by the same resilient diaphragm that is used for the movable contacts. Such an arrangement appears in the above mentioned patents by Gee, Hsieh, Nakayama, Shirai and Smith, and causes increased friction and wear. The effort for parts reduction also caused the designers to use central supports for the movable members that are a part of the casing, and therefore have a considerable amount of slack or play. The movable member has considerable sliding effects in addition to its tilting motion. This results in inaccurate actuation of the switches. In addition, except for U.S. Pat. No. 4,975,547 by Nakayama, no effort has been made in the above patents to delimit the tilting motions of the movable member if pressure is applied in intermediate directions. In such cases, two switches might be activated simultaneously. This effect is utilized in the patent by Chandler to encode intermediate directions. However, such an effect is not reliable enough due to the inaccuracy of the tilting mechanism and flexibility of the resilient material. In summation, the structure of the switching devices described above, is unsuitable for accurate multi-position switches with more than four positions. Such a switch requires more accurate tilting and switching mechanisms.